The primary objective of the second year work was the elucidation of the structure and biochemical applications of polyacrolein (PA) microspheres. Fourier Transform IR Studies were confirmed by solid phase carbon 13 NMR spectra, and a PA structure was proposed to account for the IR and NMR results. New procedures were developed to synthesize PA radiation-grafted monodisperse magnetic and nonmagnetic polystyrene microspheres. Studies were initiated to determine the feasibility of cell separation and depletion of T cells from bone marrow by means of these microspheres in collaboration with members of the Sloan Kettering Cancer Institute as well as with members of the Imperial Cancer Institute in London. The covalent binding of antibodies (first step) and antigens (second step) to radiation-grafted polystyrene spheres of uniform size was confirmed by use of radiolabeled proteins. The covalent binding of radioactive antibodies to PA microspheres present in a film of agarose was demonstrated. The chromatographic separation of 100-angstroms PA particles made fluorescent with Lucifer Yellow was studied. These particles were separated from free fluorochrome and from fluorescent particles of larger than 100-angstrom diameter particles. (A)